A delay in closure (ossification) of the anterior fontanelle, which generally undergoes closure around the 18th month of life. The phenotype is Human Phenotype Ontology term HP_0001476 (Delayed closure of the anterior fontanelle). Also known as: Delayed closure anterior fontanel, Delayed closure of anterior fontanelle, Delayed closure of the bregma sutures, Late closure of anterior fontanelle, Late closure of large anterior fontanel, Late closure of the bregma sutures, Later than typical closing of soft spot of skull, Persistent anterior fontanelle.